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+--- Thread: Output from NMEA 0183 to SeaTalkng convertor (/showthread.php?tid=2896)
Output from NMEA 0183 to SeaTalkng convertor - Lew Springer - 04-17-17 08:39 AM
I am using two NMEA 0183 to SeaTalkng convertors in my system. The units are fed by a GPS via the SeaTalkng backbone and powered by 13.65 volts. In an open circuit condition and the plus output is a steady 13.65 volts and the negative output toggles from 0.64 volts to 12.1 volts. This doesn't seem right as the plus output is always above the negative. My two Icom receivers accept the data properly but a third unit (stabilizer) does not. Shouldn't the plus output be more like 6 volts or so?
I thought one signal line was supposed to be higher than the other for a "1" state and that they reverse for a "0". Any tips you can provide will be appreciated.
Is an equivalent circuit schematic for the convertor output available?
RE: Output from NMEA 0183 to SeaTalkng convertor - Chuck - Raymarine - Moderator - 04-18-17 02:24 PM
Welcome to the Raymarine Forum Lew,
Q1. I am using two NMEA 0183 to SeaTalkng convertors in my system. The units are fed by a GPS via the SeaTalkng backbone and powered by 13.65 volts. In an open circuit condition and the plus output is a steady 13.65 volts and the negative output toggles from 0.64 volts to 12.1 volts. This doesn't seem right as the plus output is always above the negative. My two Icom receivers accept the data properly but a third unit (stabilizer) does not. Shouldn't the plus output be more like 6 volts or so?
A2. Please click here to view a FAQ addressing this subject. When operating in NMEA 0183 mode within a SeaTalkng/NMEA 2000 backbone in which GPS data is present, an analog meter's needle should bounce between approximately +0.3VDC and +5VDC. Raymarine product's can support up to three NMEA 0183 listeners. However, it is sometimes necessary to install a NMEA 0183 expander when interfacing more than two NMEA 0183 listeners to the Raymarine device. Should an analog meter connected between NMEA 0183 OUT+ and NMEA 0183- leads from the SeaTalk to SeaTalkng Converter not behave as stated here, then it is recommended that SeaTalk to SeaTalkng Converter be tested by Raymarine’s Product Repair Center.
Q2. Is an equivalent circuit schematic for the convertor output available?
A2. Unfortunately, schematics are not available for currently manufactured Raymarine products.
RE: Output from NMEA 0183 to SeaTalkng convertor - Lew Springer - 04-18-17 09:12 PM
Chuck,
Thanks for your response. Unfortunately it did not answer all my questions. I have a SeaTalkng converter powered by 13.65 volts. It in turn powers an RS130 GPS via a backbone. A proper load is at the GPS sensor and on the open end of the convertor. An MFD is also attached to the convertor via a SeaTalkng spur. I know the GPS is operating properly because the MFD receives and processes the position sentences.
When I put an oscilloscope on the NMEA 0183 connections (scope is the only load) I get the results in the attached PDF sketch. This doesn’t look right to me. Is this the expected open circuit output from the convertor? Note that the ve+ voltage is always higher than the ve- voltage. My Icom 604 receiver accepts and displays the proper data.
RE: Output from NMEA 0183 to SeaTalkng convertor - Chuck - Raymarine - Moderator - 04-19-17 04:11 PM
Lew,
The NMEA 0183 waveform that we observed with one of our SeaTalk to SeaTalkng Converters started from a +5.8 VDC level which peaked at approximately +13 VDC with each pulse. Regarding the third device (stabilizer) which is not processing NMEA 0183 data from the SeaTalk to SeaTalkng Converter, you may want to try connecting the third device's NMEA 0183 IN+ lead to the NMEA 0183 OUT- lead of the cable connected to the SeaTalk to SeaTalkng Converter and connect the the third device's NMEA 0183 IN- lead to the NMEA 0183 OUT+ lead of the cable connected to the SeaTalk to SeaTalkng Converter to see if the third device then responds to the NMEA 0183 signal produced by the Converter.